San Franciscans should have no illusions about the dueling reform measures on the Nov. 8 ballot: Neither would come close to covering the escalating general-fund obligation to meet promised pensions and health-care coverage for retired city workers. Propositions C and D offer only modest down payments on the reforms that must be pursued to keep these retirement costs from overwhelming the city's ability to maintain basic services.

But either measure offers some progress on a math problem that has been ignored for too long. If voters fail to act, the city could be looking at annual pension obligations of perhaps $800 million by fiscal 2015-16 - double the current hit to the general fund.

The choice comes down to Prop. C, a 10-year, $1.3 billion savings negotiated by the establishment (politicians, labor, business leaders) and Prop. D, a 10-year, $1.6 billion savings pushed by Public Defender and mayoral candidate Jeff Adachi and put on the ballot through signature gathering.

Adachi deserves great credit for forcing City Hall to confront an inconvenient truth: It has been making grand promises to city workers for pensions and retiree health care without making provisions to pay for them. His 2010 tough-love pension reform plan, Prop. B, while falling short, jolted the establishment into action.

What emerged were months of talks among business and union leaders and politicians - especially Mayor Ed Lee - that produced the outlines of Proposition C. While the math may come at least a couple billion dollars short of a solution, the measure reflects a sober and multifaceted attempt to address this funding shortfall.

Here are the key ways Prop. C is preferable to Prop. D, all of which can be attributed to the value of bringing various stakeholders to the table.

Consensus: The very fact that business and labor leaders are supporting Prop. C bodes well for its passage and acceptance - and sets the stage for productive, mutually respectful talks on further reforms that will almost certainly be needed to address this pension and health-care shortfall.

Legality: Prop. D invites lawsuits by peeling back vested pension rights without offering new benefits in return. Case law seems pretty clear on this point: Vested rights can be revoked only in exchange for something of comparable value.

Scope: Prop. C, while generally not as aggressive on constraining pension formulas as Prop. D, covers several critical areas that its counterpart ignores. For example, Prop. C would require existing city employees to eventually contribute 1 percent of their salaries toward their retiree health benefits; Prop. D does not touch that issue. Prop. C would eliminate a city match for an annuity accrued by city employees who work five years but don't stay long enough to qualify for a regular pension - under Prop. D, high-paid workers, such as lawyers, would actually receive a windfall with a guaranteed match of their elevated contributions. And Prop. C would address one of the hidden cost drivers of city benefits: the employee-dominated composition of the Health Service System board. Under Prop. C, the board would be rebalanced with three members each for workers and management, with the city controller appointing one board member.

"I lost dozens of votes 4-3 that cost the city tens of millions of dollars," said Supervisor Sean Elsbernd, a fiscal hawk who has served on the board.

The personalized nature of this campaign - and even the negotiations that led to Prop. C - has been regrettable. There is something very wrong with San Francisco politics when labor leaders can dictate that Adachi cannot participate in the discussions on an issue of such consequence that he brought to the fore. There is also something wrong when City Hall's definition of "all stakeholders" does not include the vast majority of taxpayers who are paying the freight and whose own pensions do not come close to even these scaled-back proposals.

Still, San Franciscans have a choice to make. For all the reasons stated above, Prop. C is superior to Prop. D - and, as Mayor Lee has so pointedly noted, the "worst situation we could ever face" is a continuation of the status quo. He is absolutely right; it's time to act, even if the options before us are decidedly incremental.

We recommend passage of Prop. C.

How the measures compare

Pension formula for police and firefighters{+1}

Current: 3% of final salary (average final two years) X years of service at age 55.{+1} (Pension for 30-year veteran who earned $100,000: $90,000 at age 55).

Prop. C: 3% of final salary (average final three years) X years of service at age 58. (Pension for 30-year veteran who earned $100,000: $90,000 at age 58).

Prop. D: 2.7% of final salary (average final five years) X years of service at age 57. (Pension for 30-year veteran who earned $100,000: $75,000{+2} at age 57).

Employee pension contribution, $100,000 salary{+3}

Current: 7.5% of salary

Prop. C: Between 2.5% and 12.5% of salary, depending on level of city contribution. As city's cost rises, so does employee's.

Prop. D: Between 7.5% and 15% of salary, depending on level of city contribution.

Employee contribution to retirement health care

Prop. C: Pre-2009 employees must contribute 0.25% of salary starting in fiscal 2016, increasing by 0.25% of salary annually to a maximum 1%.

Prop. D: Does not change current system.

{+1}For other city employees, the formula is 2.3% of final salary X years of service at age 62. Both propositions would raise the retirement age for maximum pension to 65. Changes apply to new hires only; would not affect vested rights. {+2}Prop. D reduces the maximum possible pension for public safety workers (now 90%) to 75% for new hires (same as for other city employees). Prop. D also imposes overall pension cap of $140,000; Prop. C has no such ceiling. {+3}Example is for non-public safety employees.